With the advent of endovascular coring and collecting catheters, the helical cutting catheter and filtration tip endovascular guide wire, it is possible not only to open but to remove all atheroma from a defined length of partially occluded arteries with minimal risk of downstream embolization. Furthermore, this can be carried out through a single entry point in the artery, as compared to earlier techniques using the Hall Loop or Cannon Dissector, both of which require two points of entry.
Apparatus and methods, such as those disclosed in U.S. Pat. Nos. 5,071,424 and 5,074,871 are used to perform near total removal of an atheroma. However, when treating atheroma such as in lower limb ischemia in the superficial femoral artery, occlusions are sometimes complete or nearly complete making use of presently available endarterectomy apparatus in removal of the atheroma very difficult, if not impossible. Otherwise useful presently available endarterectomy devices require at least a portion of the device to be positioned through and distal to the atheroma before excision can begin. When stenosis of a vessel is so bad that operation of the presently available endarterectomy devices is prohibited due to severe obstructive stenosis, the vessel must be at least partially opened to provide a pathway before the other endarterectomy devices can be efficaciously used.
One of the critical problems which must be addressed when clearing a pathway in a completely or nearly completely obstructed artery is binding of a cutting tip or associated sleeves and catheters within the obstruction. Another problem is clearing a pathway without excising material from the atheroma under circumstances where recovery of excised particles is difficult. Still another problem deals with a need to exchange cutting tips as a need for different pathway diameters and various hardnesses of tissue are encountered during the opening of a pathway. One further important problem is providing a clean, sterile instrument for each procedure. Parts used to clear obstructive tissue from arteries involve extremely small and intricate parts into which excised particles are often captured for recovery from an excised site. Appropriate safe and efficacious cleaning and sterilization of used instruments for reuse is usually impractical, if not impossible.